Under sunveillance

Could you cope without the numerous electronic devices that help you get through the day? You might have to if extreme space weather heads our way.

Solar Maximum

Every 11 years the Sun enters a period of heightened activity – a solar maximum. At solar maximum, the Sun’s twisted magnetic field unwinds by breaking at certain points and reforming in a more relaxed state. In doing so, the Sun releases huge amounts of ultraviolet and X-ray radiation in the form of solar flares, as well as hot plasma in coronal mass ejections. And it’s these coronal mass ejections, or CMEs, that make up the extreme space weather events that pose most danger to us on Earth.

Watching, waiting

When a CME is released, scientists scramble to see whether it will affect the Earth. Data from the few satellites that monitor the Sun is fed into computer models to forecast an arrival time at Earth, but with only limited amounts of information available, the best predictions are still a few hours out.

In addition, not all CMEs of the same size affect the Earth in the same way. The Earth is more vulnerable to CMEs when the magnetic fields of the Earth and CME combine. The potential for this to occur, what scientists call geoeffectiveness, increases when the two magnetic fields are pointing in opposite directions.

New measures

Currently, the only way to determine the direction of the magnetic field inside a CME is from data collected by an ageing NASA probe called ACE. Launched in 1997, ACE is located at the first Lagrangian point – a point in space along the line between the Earth and the Sun where the gravitational pulls balance. Spacecraft can stay at this point for many years using little fuel, but its short distance from Earth means that ACE can only give 30-60 minutes warning of what’s heading our way.

Jim Wild, a scientist from Lancaster University studying aurora, says that being able to predict the direction of the magnetic field of a CME before it arrives at the Earth is “a nut we’d like to crack”. Scientists are working on a new method that relies on observing changes in very long wavelength radio waves from distant stars as they travel through a CME. However, Mike Hapgood, plasma scientist and advisor to the UK government on space weather risks, admits it’s still early days, “It’s not been tried before and the new technologies like new radio telescopes are just getting to the point where it might be possible.”

Consequences

Extremely large CMEs, with the potential to cause widespread disruption to electronic devices, occur every few hundred years. In 1859 the magnetic field of the Earth was disrupted so much by a CME, the aurora borealis was seen as far south as Hawaii and telegraph stations caught fire.

With our modern day reliance on electronics many industry sectors are taking extreme space weather seriously even though many of the precise effects of an extremely large CME are unknown. “I’m much happier there are conversations going on now at a top level between government, industry and science to quantify impact on the technological systems we use” says Jim Wild.

If a CME were to cause a power grid to shut down, there would be huge consequences. “Today it’s a big deal. Without power you don’t have refrigeration which is important for food and medicine, you lose all communication and most importantly there would be no electronic money – ATMs won’t work, debit cards won’t work” says Mike Hapgood.

This is another great chance for the world to unite, share expertise and work together as Mike says, “This is a global problem. We’re all in this together. If you had a really big event, there aren’t any safe places on Earth.”